RE: LTE-M PSM Edge Cases and Questions

Hakon — Tue, 12 Nov 2019 14:45:18 GMT

Hello,

[quote user=""]Is PSM part of LTE Cat M1?[/quote]

No, it's also used in NB-IoT.

[quote user=""]Does every MNO supporting LTE Cat M1 also support PSM?[/quote]

No, and the choosing of TAU and active time is often restricted.

[quote user=""]How much can the MNO dictate the PSM TAU and active time I’m allowed to use?[/quote]

The MNO controls the TAU and active time at it's own discretion.

[quote user=""]Is it possible to check from the device if the current carrier supports PSM?[/quote]

You can try to set PSM and see if it's rejected.

[quote user=""]If we request PSM but the MNO does not support it, how do we detect this?[/quote]

Run

AT+CEREG=5

and read the last two parameters.

[quote user=""]Can we exit PSM if we start roaming? How do we detect this?[/quote]

You can use the AT+CPSMS command.

[quote user=""]Can we exit PSM for any other reason? How do we detect this?[/quote]

You can use the AT+CPSMS command for this too.